Autoreactivity to sweat glands and nerves in clinical scabies infection

CONTEXT: Skin changes in pregnancy can be categorized as 1) physiological/hormonal, 2) alterations in pre-existing skin diseases, or 3) represent development of new dermatoses, some of which may be pregnancy specific. CASE REPORT: We describe a 19 years old female at 27 weeks gestation who presented with a rash on the face and breast, with intense pruritis. Hematoxylin and eosin demonstrated Scabies mites within the epidermis, with an intense perivascular infiltrate of lymphohistiocytic cells around the superficial dermal blood vessels. By direct immunofluorescence (DIF), human fibrinogen was also detected in the perivascular areas. DIF also revealed deposits of human IgG and complement C5-9/MAC deposits in the sweat glands, as well as in nerves surrounding the sweat glands subjacent to the mites. Overexpression of ezrin and junctional adhesion molecule antibodies close to the scabies infection sites were also seen. CONCLUSION: Given that the hallmark of clinical scabies is intense pruritus and that very limited information is available regarding the pathophysiology of this symptom, we suggest that the itching sensation may be exacerbated by nerves and eccrine sweat glands in close proximity to the sites of infection.